Systemwide Events Calendar

Oceanography Seminar

“Interactions between microbes and dissolved organic matter in tropical reefs: What role might bacterioplankton play in ecosystem trajectories?”

Abstract: While emerging global-scale trends in ocean chemistry and physics loom large over all marine ecosystems, coral reefs worldwide have already exhibited striking changes in the last century. Increasing abundance of benthic algae and concomitant declines in coral cover are perhaps the most widespread and tangible evidence of reef "degradation" associated with human activies and population growth. However, the fundamental changes to ecosystem biogeochemistry and metabolism on degraded reefs lie in the world of microbes: Human-impacted coastal habitats exhibit characteristic shifts in the size, abundance, and community structure of microbes, and there is compelling experimental evidence suggesting that the spread of algae may facilitate reef degradation through changes to interactions between microbes and their dissolved organic matter resources.

Bacterioplankton (planktonic single-celled Bacteria and Archaea) are now widely recognized as major contributors to pelagic food webs and as a significant fraction of the diversity and productivity of the global ocean, but their role in coastal habitats is poorly understood. These organisms are the primary conduit for recycling the vast, complex pool of dissolved organic matter (DOM) in the oceans; DOM-microbe interactions in reef environments may be central to understanding how reefs are changing now and how they will adapt in the future. This talk will present our current understanding of the types of bacterioplankton in reefs, the biogeochemistry of DOM in reefs, and how the composition of the benthic macroorganismal community may influence microbial dynamics and reef metabolism.